1. Field of the Invention
The present invention generally relates to an inner-rotor motor and a rotor of the inner-rotor motor and, more particularly, to a rotor having an iron core and an inner-rotor motor using the rotor.
2. Description of the Related Art
FIG. 1 shows a rotor 9 of a conventional inner-rotor motor. The rotor 9 includes a shaft 91, an iron core 92 and a plurality of permanent magnets 93. The iron core 92 includes a tubular connection portion 921 fitted around the shaft 91. The tubular connection portion 921 is connected to a plurality of magnetic pole portions 922. The quantities of the plurality of magnetic pole portions 922 and the plurality of permanent magnets 93 correspond to the quantity of the magnetic poles of the rotor 9. The iron core 92 includes a plurality of magnet-receiving gaps 923 extending through the iron core 92 in an extending direction of the shaft 91. Each of the plurality of magnet-receiving gaps 923 is located radially outward of the tubular connection portion 921 between two adjacent magnetic pole portions 922. In this arrangement, the plurality of permanent magnets 93 can be respectively received in the plurality of magnet-receiving gaps 923. One embodiment of such a rotor 9 can be seen in China Patent No. CN202759303.
In this arrangement, when one permanent magnet 93 is received in a magnet-receiving gap 923 between two adjacent magnetic pole portions 922, each side of the surface of the permanent magnet 93 in a circumferential direction of the rotor 9 can be securely coupled with the lateral surface of a respective magnetic pole portion 922. However, there exists a gap 94 between the tubular connection portion 921 and the permanent magnet 93, leading to an insufficient bonding effect between the iron core 92 and the permanent magnet 93. As a result, during the rotation of the rotor 9, the permanent magnet 93 may displace in the magnet-receiving gap 923 or may even disengage from the magnet-receiving gap 923. Thus, the rotor 9 is unbalanced during the rotation thereof, leading to the generation of noise or vibration.
To solve the problem, the gap 94 may be filled with an adhesive to reinforce the bonding effect between the permanent magnet 93 and the iron core 92. However, the use of the adhesive will increase the complexity of the production procedure. Moreover, the permanent magnet 93 needs to bear a radially outward inertia force during the rotation of the rotor 9, leading to the deterioration or disengagement of the adhesive after a long term of use. Disadvantageously, the service life of the rotor 9 is shortened.
In light of this, it is necessary to provide a novel inner-rotor motor and a rotor of the inner-rotor motor. As such, the problems in regard to noise, vibration, complex production procedure or short service life can be solved.